From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0794EC433E0 for ; Thu, 24 Dec 2020 13:50:15 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AA1C522287 for ; Thu, 24 Dec 2020 13:50:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA1C522287 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1DB1F892CD; Thu, 24 Dec 2020 13:50:14 +0000 (UTC) Received: from mail-qk1-x733.google.com (mail-qk1-x733.google.com [IPv6:2607:f8b0:4864:20::733]) by gabe.freedesktop.org (Postfix) with ESMTPS id 15CCE892CD for ; Thu, 24 Dec 2020 13:50:13 +0000 (UTC) Received: by mail-qk1-x733.google.com with SMTP id h4so2101676qkk.4 for ; Thu, 24 Dec 2020 05:50:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=tWzy6LjCibC0JQQvRPBI8FHsR4ZBmpIkexvbUByVFMI=; b=heXmjtK6dRGqcrtk5NWPSa9ElXxxzbou9th2oKMkGqwvi8YZkFr6hWFVcr2pW6sl9H T9WXewqtEoBrO0S9A/4qA7vsLwuAvhCVi+TvbzxAp5ahh2HScDbhinlvQGbNDxXi5ATO rSYp22bO3SkrwAYJ0US0ePfGmfRngjycGesZ1uMQDK6YYXKZ1qbSmKOys8RuG/2GnYch sTBjWyRqd8jCiSlaoZUZkZSynpn8QlvNIefPYl2VmQclL1FVSjZ2klOOrXV2aCvyopRJ wnrDxaaQJLq8EatMG817b1kNce7UB4nIVW99yvpCb/1KWdPGDmtFhRWK075Stuj3Z7OL l9UA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=tWzy6LjCibC0JQQvRPBI8FHsR4ZBmpIkexvbUByVFMI=; b=odqrkJFbJjAtnmkfZwXfdKldFHIbyIN8slKsDFkejOdRpmt9cldwd8e3dYFrohYa6I 6BNxDAtUcZQNIsyP0aPsSv4PdvbJRIEeONwNaHRL1hT/cRQp4P4QGB3B9nRIkubtBTnn 58BEFmUXs05oHTxtf3y7p9Ix47KErBvnE9rhJYJep5v6yEPkCpQSc/3bPrZnfuve7Wvl K6GYvRhuG51Yf6eZ9RGlT42UDT3I9DxaZel5wxNgIh4Z59zW1RchSSOFZslSto70oc96 fNoAqqjFSewAC23N1krWfTChAXL4I0FQLmPgNQEv+AJGmdRtErObz3E7Mp/aDLV8Qn3J TvOQ== X-Gm-Message-State: AOAM530HPm2q55mDgZ0i7+k0eRbMDT3Uu+m647pM0rVuvwpFsRrd4KFk GA+GX/7kAPFzb5IP0i3eyzetxiCnsoyzX7SBVTT2JUmw X-Google-Smtp-Source: ABdhPJymGZbRLckKLGyXP7pbBUoZwDPoIcyxeAgbGJiDrJKIki0qwZ/bofLm9yrNbQKR2z0YSvxdmw27wr+qH9OysgQ= X-Received: by 2002:a37:a8a:: with SMTP id 132mr30306045qkk.327.1608817812277; Thu, 24 Dec 2020 05:50:12 -0800 (PST) MIME-Version: 1.0 References: <20201223111126.3338-1-chris@chris-wilson.co.uk> <20201223111126.3338-7-chris@chris-wilson.co.uk> In-Reply-To: <20201223111126.3338-7-chris@chris-wilson.co.uk> From: Matthew Auld Date: Thu, 24 Dec 2020 13:49:46 +0000 Message-ID: To: Chris Wilson Subject: Re: [Intel-gfx] [PATCH 07/62] drm/i915/gt: Resubmit the virtual engine on schedule-out X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Intel Graphics Development Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, 23 Dec 2020 at 11:12, Chris Wilson wrote: > > Having recognised that we do not change the sibling until we schedule > out, we can then defer the decision to resubmit the virtual engine from > the unwind of the active queue to scheduling out of the virtual context. > This improves our resilence in virtual engine scheduling, and should > eliminate the rare cases of gem_exec_balance failing. > > By keeping the unwind order intact on the local engine, we can preserve > data dependency ordering while doing a preempt-to-busy pass until we > have determined the new ELSP. This means that if we try to timeslice > between a virtual engine and a data-dependent ordinary request, the pair > will maintain their relative ordering and we will avoid the > resubmission, cancelling the timeslicing until further change. > > The dilemma though is that we then may end up in a situation where the > 'demotion' of the virtual request to an ordinary request in the engine > queue results in filling the ELSP[] with virtual requests instead of > spreading the load across the engines. To compensate for this, we mark > each virtual request and refuse to resubmit a virtual request in the > secondary ELSP slots, thus forcing subsequent virtual requests to be > scheduled out after timeslicing. By delaying the decision until we > schedule out, we will avoid unnecessary resubmission. > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2079 > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2098 > Signed-off-by: Chris Wilson > Cc: Tvrtko Ursulin Reviewed-by: Matthew Auld _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx